Earlier today news broke that Yaegashi wasn't going to retire but instead will resume his career later this year. His intention however is to ditch any plans of continuing to fight at 108lbs and instead will be fighting at either Flyweight or even Super Flyweight.
At the moment there is no date set for his return though we're hoping that he will get the chance to have a long break, give his body a serious rest and then continue with his career. In a perfect world he would begin his comeback at a low level, see how he feels and then work his way through tougher foes. Knowing Yaegashi as a fighter however it's fair to say he'll want to get straight into tough fights and this may be an issue.
(Image, of Yaegashi with stable mates Satoshi Hosono and Seiichi Oakada, courtesy of Hideyuki Ohashi's blog)